Abstract : In support of the task objective of formulating design criteria for thin-shell concrete structures to withstand dynamic loading, experiments were performed to obtain information about the behavior of thin-section reinforcedconcrete members subjected to dynamic compression. Information was obtained on the dynamic material strength and on the characteristics of the failure process. The test members were planar concrete panels reinforced with a single layer of square-meshed welded-wire fabric. Several combinations of panel thickness, reinforcingwire diameter, and mesh size were investigated, as well as two concrete strengths (4,000 and 7,000 psi) and a single rate of compressive-stress application (100,000 psi per second). The results of the experiments show that the dynamic material strength of thin, compressively loaded members can be estimated as the sum of the dynamic concrete-failure load and the dynamic steelyield load as long as estimates of dynamic concretefailure load are based upon concrete cylinder strength and estimates of dynamic steel-yield stress do not exceed the maximum stesss prescribed for static design by the ACl Code (ACl 318-63). During the failure process, high-strength concrete was found to expel more particles, traveling at higher velocities, than normal-strength concrete, and some types of reinforcing mesh were found to initiate expulsion of large pieces of concrete. These two failure characteristics, among others, are illustrated in the report by the use of extracts from high-speed photography of the tests. (Author)